1. Field of the Invention
The present invention relates to a magnetoelectric generator for generating electric power by electromagnetic induction between a permanent magnet and a generating coil due to rotation of a flywheel.
2. Description of the Related Art
Conventionally, magnetoelectric generators are known in which a plurality of permanent magnets are fixed to an inner peripheral wall surface of a cylindrical portion of a bowl-shaped flywheel so as to be arranged circumferentially, and the permanent magnets are fixed integrally to the flywheel by filling a resin material between adjacent permanent magnets (See Patent Literature 1, for example).
In these magnetoelectric generators, a plurality of protruding-portions projecting inward are formed on the cylindrical portion of the flywheel by press working, and the resin material is engaged by these protruding portions to prevent the resin material and the permanent magnets from moving relative to the flywheel.
Patent Literature 1
Japanese Patent Laid-Open No. 2002-101630 (Gazette: Page 5; FIGS. 1 and 2)
In the flywheels of conventional magnetoelectric generators, a bar-shaped material is machined into a bowl shape, then press working is applied to form the protruding portions, but roundness of the flywheel deteriorates during this press working, as shown in FIG. 5, giving rise to irregularities in an amount of air gap between the permanent magnets and a stator.
In particular, since flywheels are being made thinner in magnetoelectric generators with a view to reducing size and weight, deterioration in roundness of the flywheel as the protruding portions are being formed on the cylindrical portion by press working has become marked, and due to increases in irregularities in the amount of air gap resulting from press working, problems such as the following have arisen:
A) Fluctuations arise in the rotational locus of the rotating flywheel and adversely affect power generating characteristics (output characteristics);
B) Sliding friction arises between inner peripheral surfaces of the permanent magnets and outer peripheral surfaces of the stator, possibly preventing completion of manufacture; and
C) Temperature differences may also arise in generating coils of the stator due to power generating effects (alternating magnetic field) from increases and decreases in the amount of air gap, reducing service life and reliability of an electrically-insulating coating (a polymeric material) on conducting wires in a portion of the generating coils due to extreme temperature increases.